Hi Jonas,
I have reported 3 trees two weeks ago (attaching photos of one of them. they look the same more or less)
They developed a dens root ball in a year… I managed to open it and worked on the nebari before moving them to a colander for a few years.
My question is, was opening the root ball a mistake at 2 years old? I left lots of roots and was relatively gentle… I hope the first 3 will make it because they have huge potential.
I have some more to repot and don’t want to lose them.

Hi Shay
Looks like a great job to me. It is wise to get the basic root work done when the tree is younger and that approach will set it up well for the next step in the colandars. I have found that i still need to check them at least every year when they are young as they grow very vigorously.
Jonas may have some extra thoughts, but you seem to have followed the same process i do and it has worked well for me. Taking off the circling roots, cutting back the thick ones, keeping the fine, and taking off the down roots.
Well done!
Best in Bonsai

Thanks Frank!
Is there any way of knowing when is the best time for the tree to do that (repot)? Like bud swelling in deciduous for example.
I saw lots of new roots and its getting hotter and hotter here so I figured its OK. But if there is a better sign for it I’d like to know…
I have a ROR in a colander that just got in to its 4th year and its exploding with roots… I am under the impression that the firs years in a colander are crucial for a healthy and dense root ball. When is it too much roots?
Thanks again!
Shay

I repot pines just before or as they become active in the spring. Before the candles start to move. In my neck of the woods that is usually March/April. it will be earlier this year and i am starting repotting this week. This gives the tree the best recovery time as it begins an active growth season. I agree that the first formative years are the best opportunity for creating desireable root ball formation. The colandar concept was intended to air prune and prevent long tap or escaping roots. I think it works very well to a point. I have settled on using the first four years to get as much growth combined with a good start on the root ball formation. I find it hard to imagine too many roots unless they are too long and too thick for Bonsai pots. I try to create good strong short fat basic nebari with as many feeder roots as possible until it starts to lift out of the container and needs a repot.
Basically this is an outline of the timing. Sow seeds January
Seedling radial cut ( 2nd set of needles) approx 60 days ( March ) indoors.
move to 4 inch pot 6 months ( no root work) ( August )
Move to colandar March year one ( selective root work some cutback)
Colandar goes on bench ( air root prune)
March year two ( root prune place back in colandar, put colandar in grow bed)
March year three ( cut escaping roots, rotate and put back in grow bed)
March year four ( remove from colandar, root work to escaping roots, circling roots or strong downward roots. Small amount of work if surface roots need attention or root graft on one side needed, otherwise the least amount of disturbance to the overal rootball ) Usually change surface soil to maintain great drainage. The reason for limited root work at this point is to retain vigorous growth for trunk development. one of the prime focussses for year four to eight.
Note: At this point I abandon the colandar and use either an anderson flat or purpose built grow box. I use the smaller deep propagation style anderson flats for smaller size and better depth. 14 by 14 by 5 inches deep. If i am preparing shohin or smaller pines the grow boxes are 11 by 11 and 4 1/2 inches deep.
These points are specific for developing young pines, suited to this stage of vigorous growth and fast recovery.
My Nursery is facing south and exposed to full sun in a warmer micro-climate.
Hope these notes are of some use.

Hi Frank,
Thank you for your notes!
I am doing this for the past 3 years and every year I try to grow 100 seedlings. Its going pretty well and I am following Jonas’s method with soil adaptation to what I have here. Its the first time anyone has succeeded growing JBP for that long in Israel. The way they look I think they will stay here for a long time…
The main difference from your timeline is I skip the august repot, do root work after year 1 and another root work at year 2 with a change to a colander. it seems they build up a compact root ball after 1 year and maybe adding the colander after 6 months will prevent that. the only problem for me is space…
The later notes will help me in the future. thank you again!
shay.

Your Welcome
Space is always an issue. My first crop of Pines were germinated in 2010 and i have been adapting methods and space requirements since that time. Now at age 70 i have decided that i have enough seedlings and it would be a good idea to reduce the number i have to care for each year.
Fortunately i am teaching developmental workshops and their is a demand from local Bonsai Artists for Pines developed specifically for Bonsai.
I expect your climate is warmer and drier than mine, the pines should do very well if there is sufficient dormancy period.
Will be interested to hear of your progress and ideas going forward.
Best in Bonsai
Frank Corrigan

Hi Shay
I thought you might enjoy a picture of one of the 4 yr JBP. I just finished a repot from the colandar to the grow box. This is the first of this season and i will greenhouse it now until the risk of frost passes.
This is 62.5 cm tall and 2.5 cm diameter trunk. I cutback the apex leader at the beginning of year three to produce lower branching and budback. I follow Jonas’s advice and reduce branching only when it will interfere with trunk development. The exception being the leader once growth is ramping up in the spring. Then i follow a suggestion from Gary Wood to reduce needles and side branches on the top apex not intended for future styling. Now i have only 153 of the 4yr trees to repotleft this spring.